The present invention relates generally to devices for facilitating the ability to climb. More particularly, this invention concerns portable ladders of the type used by sportsmen.
Sportsmen often desire elevated locations for observation. In the case of hunters, the purpose for as elevated observation location can be for spotting potential game, for enhanced concealment from potential game, for an improved vantage point for shooting at potential game, or for some combination of those purposes.
Since trees occur naturally in areas where sportsmen and hunters typically seek elevated observation locations, sportsmen and hunters have, in the past, used available trees for that purpose. Climbing trees can be difficult, especially if there are no relatively low hanging branches. In addition, if the sportsman or hunter wants to take a rifle, shotgun, hunting bow, spotting scope, or other device to the elevated observation location, it may be even more difficult to climb a tree.
To aid sportsmen and hunters to climb trees, various kinds of ladders have been proposed in the past. For example, an access ladder has been suggested which uses a plurality of sections each having a single tubular support, a plurality of cantilever-mounted rungs extending from the support, and a hook, chain, turnbuckle arrangement to secure prongs of the ladder section to a tree. See, U.S. Pat. No. 4,411,335, issued to Forrester on Oct. 25, 1983. Such cantilever-mounted rungs are prone to bending and resultant danger to the sportsman or hunter. A singular tubular support does not provide lateral stability and can easily sink into topsoil. Prongs which penetrate tree bark are undesirable not only since they deface trees but also because they expose trees to insect infestation and damage.
Another ladder assembly has been proposed using progressively narrower, pivotally connected ladder sections with a tree stand, a stand-off strut in the middle of one ladder section, and a chain with turnbuckle arrangement to attach the strut to a tree. See, U.S. Pat. No. 4,742,888, issued to Amacker on May 10, 1988. Such a stand-off strut does not provide significant lateral stability to the ladder. Moreover, the assembly is quite heavy since it is unnecessarily wide. Furthermore, the assembly has a fixed length due to its pivotal arrangement which restricts its usefulness where the height to be climbed is variable.
A tree ladder is also known having a pair of sections with cantilever mounted rungs and a limb-engaging hook assembly. See, U.S. Pat. No. 4,762,200, issued to Andrews et al. on Aug. 9, 1988. The central tubular support and cantilevered rungs are objectionable as noted above. And, the fixed length restricts utility, as noted above.
There are other types of light-weight ladder structures such as, for example, the fire escape ladders of U.S. Pat. No. 782,539, issued to Bihl on Feb. 14, 1905, U.S. Pat. No. 644,265, issued to Thirion on Feb. 27, 1900, and U.S. Pat. No. 896,569 issued to Neal on Aug. 18, 1908.
From the foregoing discussion, it will be seen that the need continues to exist for a light-weight portable ladder assembly which overcomes problems of the type discussed above.
An extremely rigid, light-weight, portable ladder with substantial lateral stability and having capacity to be erected while being climbed has been found. This portable ladder features one or more ladder sections which can be telescopically or slidably connected together and to a base section. The ladder sections feature a pair of generally parallel rails spaced from one another by a distance selected to be larger than the width of a typical boot and less than twice the width of a typical boot, each rail being a predetermined length with a tubular cross section, and having an end adapted to telescopically or slidably join with an end of a similar rail. In addition, each ladder section has a plurality of rungs extending between and connected to each of the parallel rails, with one rung being attached closely adjacent to the first ends of the generally parallel rails. For attaching the ladder section to, for example, a tree, a stand-off means and a securing means are provided. The stand-off means is attached to the ladder section closely adjacent to the one rung, positions the ladder section at a predetermined distance from the tree, and resists lateral movement of the ladder section relative to such tree is attached to the ladder section closely adjacent the one rung. The securing assembly attaches to the ladder section and secures it to the tree at the location of the stand-off device.
The base section has a pair of legs spaced farther from one another than the distance between the parallel rails of the ladder section to provide lateral stability to whole ladder assembly. In addition, the base section has a pair of parallel connector elements shaped to telescopically or slidably join with corresponding lower ends of the parallel rails of the ladder section.
The light-weight characteristics of this portable ladder assembly are achieved by keeping the length of the rungs only wide enough for one boot, and by using the stability of a tree to resist bending and buckling of the ladder structure.
Additional lateral stability relative to the tree, without environmental damage, is attained by providing a pair of tree-engaging surfaces supported by the ladder section and convergent toward the ladder section, along with a strap to secure the ladder section to the tree.
In order to provide a ladder with variable length, the ladder sections have a length selected to correspond to the average height of a man's chest above the ground. With this arrangement, the first ladder section can be attached to the tree and the next ladder section can be telescopically or slidably fixed to the first ladder section. Then, the sportsman or hunter can climb to the top of the first ladder section and secure the top of the second ladder section to the tree before any weight is even applied to the second ladder section. The procedure can then be repeated with as many ladder sections as are required to climb a particular tree or reach a particular elevated observation location.